Type



arch 2, 1943. THQRELL 2,312,782

TYPE

Filed Dec. 31, 1940 INVENTOR [aw/v 77/056624 ATTO R N EY Patented Mar. 2, 1943 TYPE Edwin Thor-ell, West Hartford, Conn., assignor to Underwood Elliott Fisher Company, New York, N. Y., a corporation of Delaware Application December 31, 1940, Serial No. 372,607

9 Claims.

This invention relates to typewriters and other printing machines and more particularly to the types of such machines.

In typewriting machines in which the work sheets are supported upon a flat or plane surfaced platen such as the Elliott Fisher machine, the types ordinarily have substantially fiat contacting faces considering the contacting face of each type as a whole. That is, the higher pertions of each type lie substantially in a. plane. In the operation of such machines, especially when a large number of copies is made, the types often cut through the work sheets along the partions of the contacting faces of the types more remote from the type centers.

The primary objects of the present'invention are to improve the construction and mode of operation of types and to produce a type construction which will avoid the disadvantage above pointed out.

With the above objects in view, the invention consists in a type embodying the novel and improved construction hereinafter described and particularly pointed out in the claims, the advantages of which will be readily understood and appreciatedby those skilled in the art.

The invention will be clearly understood from the accompanying drawing illustrating the invention in its preferred form and the following detailed description of the construction therein shown.

In the drawing, which shows, on an enlarged scale, a construction embodying the invention,

Fig. 1 is a view partly in elevation and partly in vertical section, illustrating certain parts of a typewriting machine of the Elliott Fisher type having a type embodying the invention mounted on the type bar,

Fig. 2 is a face view of a type embodying the invention,

Fig. 3 is a view in elevation of the type illustrated in Fig. 2, taken in the direction of the arrow A in said figure, and

Fig. 4 is a view in elevation of the type shown in Fig. 2, taken in the direction of the arrow B in said figure.

In the construction illustrated in the drawing, the invention is shown as applied to a typewriting machine of the Elliott Fisher type such, for example, as that illustrated and described in the patent to Foothorap No. 1,251,361, dated December 25, 1917. This machine comprises a substantially fiat platen 2 for supporting the work sheets indicated at 4 upon the substantially plane face 5 thereof, a type lever 6 which is pivoted in the manner shown in the above patent to carry the type supporting portion or head 8 of the lever toward and from the platen, and a type indicated as a whole at 9 and having a base or block it mounted on the end of a-supporting shaft or shank l2 secured in the head portion 8 of the type lever. The type,when adjacent the platen, in its operating stroke, moves in a direction substantially perpendicular to the face 5 of the platen.

The type character indicated at M is formed in relief upon the outer face of the type block I.

As above stated, when types having substantially flat contact faces or having the higher points in the contact faces located substantially in a plane are employed, a type, when brought down upon the work sheets with the force required for the proper typing of the sheets, often cuts through the sheets along the outer portions of the type and this diiiiculty occurs most frequently when a relatively large number of copies are being made.

To avoid the above disadvantage, in the'present construction, the entire contact portion I6 of the character M of the type, considering the character as a whole, is convexly curved in two directions. Thus the contact face of the character is curved convexly, in a. direction longitudinally of the character as shown in Fig. 3, the curvature being indicated by the line H in said figure. The contacting face of the character is also convexly curved in a direction transversely of the character as shown in Fig. 4, the curvature being indicated by the line bb in said figure. Both these curvatures preferably conform substantially to circular arcs or cylindrical surfaces. The axes of these two curvatures, in the preferred construction, are substantially perpendicular to each other and the curvatures are of substantially equal radii. The character may be so formed that the curvature of the contacting face or portion of the character conforms substantially to the curvature of a sphere.

The curvatures of the higher or contacting portions of the characters may have any desired radii. In actual practice, types, the contact faces of which have curvatures of equal radii of substantially two and one-half inches, have given highly satisfactory results.

With the above construction, a type strikes the work sheets with the heaviest force or blow at the central portion of the type character and this force is gradually lessened from the central portion of the character outwardly, in all directions, the force being least at the outer portions of a character. This lessening of'the force exerted by the type against the paper along the outer portions of the type has been found to be sufilcient to prevent the cutting of these portions through the paper.

It is to be understood that the invention is not limited to the particular construction illustrated anddescribed in this application but that this construction is merely illustrative of the invention and the invention may be embodied in other forms within the scope of the claims.

Having explained the nature and object of the invention and having specifically described a construction embodying the invention in its preferred form, what is claimed is:

1. A type for printing machines comprising an individual character provided with a substantially rigid ink impression face formed to print a letter or figure and having, as a whole, a convex curvature in two directions.

2. A type for printing machines comprising a character provided with a substantially inflexible contact face formed to print a single letter or figure and having, as a whole, a convex cylindrical curvature in two directions.

3. A type for printing machines comprising an individual character having the form of a letter or figure and provided with a substantially rigid contact face having, as a whole, a convex cylindrical curvature in two directions, the curvatures having equal radii.

4. A type for printing machines comprising a character provided with a substantially unyielding contact face having the form of a single letter or figure and having, as a whole, a convex cylindrical curvature in two directions about axes substantially perpendicular to each other, the

curvatures having equal radii.

5. A type for printing machines comprising an individual character provided with a substantially rigid ink impression face formed to print a letter or figure and having, as a whole, a convex curvature conforming substantially to the surface of a sphere.

6. A'type for printing machines comprising a character formed to print a single letter or figure and provided with a substantially inflexible ink impression face having, as a whole, a convex curvature in two directions longitudinally and transversely of the character.

7. In a typewriting machine, a platen having a substantially plane surface for supporting the work sheets, a type bar, a type mounted on said bar and arranged to move in a path substantially perpendicular to said surface of the platen when adjacent said surface, and comprising a character having the form of a single letter or figure and provided with a substantially unyielding ink imprinting face conforming to a convex curvature extending substantially throughout one dimension of the character.

8. In a typewriting machine, a platen having a substantially plane surface for supporting the work sheets, a type bar, a type mounted on said bar and arranged to be reciprocated in a line toward and from the platen, and comprising an individual character having the form of a letter or figure and provided with a substantially rigid contact face conforming to a convex curvature extending substantially throughout one dimension of the character.

9. In a typewriting machine, a platen having a substantially plane surface for supporting the work sheets, a type bar, a type mounted on said bar and arranged to move in a path substantially perpendicular to said surface of the platen when adjacent said surface, and comprising a single character provided with a substantially inflexible contact face having the form of a letter or figure and conforming to a convex curvature in two directions extending respectively substantially throughout two different dimensions of the character.

EDWIN THORELL. 

